The invention relates to an arrangement for checking the counting function of a number (n.gtoreq.2), of counters which are operated isochronously.
In order to check a binary counter for proper operation it is known to duplicate the counter and to apply the pulses to be counted to both counters. After each counting pulse either the counting positions or the parities generated across the counter positions are compared with each other. When it is found that counter positions are not identical or have unequal parities, an alarm signal is generated. This alarm signal is an indication that a defect has occurred in one of the two counters or in one of the two parity generators.
If a system requires a plurality of counters which are not operated synchronously but isochronously, all these counters should be duplicated if the above-described way of checking the proper operation is opted for. This implies a significant extension of the system.